91 300E stalling out while driving. - PeachParts Mercedes-Benz Forum

JordaanDMC-12 · #1 11-10-2009, 03:20 PM

Our second task has arisen! LOL

Any who, we're having a problem with our 300E stalling out on us while we drive. When it first happened there was a major loss of power and the engine became unresponsive and the tachometer would go up (but the engine rpm's would not) and the car felt as though the engine was off but still on (sorry I can't explain it any other way lol) I could step on the gas all I wanted and I got absolutely no response. I then shifted into neutral and it would fully die out. If you tried starting it back up it would crank fine and sound like it was just about to start but nothing. If I let it sit for a few minutes and cranked, it would start up like nothing ever happened.

So we changed the spark plugs and put fuel injector cleaner and it ran pretty good for a little bit but then it did it really bad after that. To the point where I had to take it back home and get the 220. But that same day (at night) I took it on a 80 mile run and it sputtered a little bit but caught itself and I immediately pulled to the side of the road, shifted into neutral and let it idle for about 15 seconds then drove off again and it didn't do it again, the entire little trip. But now after about 15 miles of driving around this morning it did it again. But this time it felt as though it was going to die out, so I shifted into neutral and pulled to the side of the road and let it idle. It was idling perfectly normal but when I put it back in drive and would accelerate it felt like it was running on 2 cylinders and was about to conk out, but if I put it back into neutral it would idle just fine. I turned it off and tried to restart it but then I got that whole cranking but not starting scenario again. I let it sit for about a minute and cranked it up and it started just fine and the whole 5-6 miles home it was 100% fine.

what do you all think? I'm totally baffled on this one..

dhjenkins · #2 11-10-2009, 04:48 PM

No engine light comes on?

Intermittant stuff like that can drive you nuts. Next time it's idling smoothly, tap on the crank sensor.

Take a look around the engine compartment for loose wires, bad grounds, etc...

JordaanDMC-12 · #3 11-10-2009, 05:18 PM

Quote:

Originally Posted by dhjenkins

No engine light comes on?

Intermittant stuff like that can drive you nuts. Next time it's idling smoothly, tap on the crank sensor.

Take a look around the engine compartment for loose wires, bad grounds, etc...

No, no check engine light or anything comes on

It's just a bummer because when we drive it, it drives great other than this problem...

It actually did it again when I went to the auto parts store. So I decided it would be a good time to really analyze it.

I put it in neutral and would try and rev it but it would not go above 20,000-30,000 rpm.. It was like something was preventing it from revving normally. If I went on the accelerator slowly then it would rev up to 40,000 to 50,000 rpm but would not go any further, it was like a governor problem or something. I turned the car off and waited a good minute or so and it started up and worked fine. It was like something had to be reset

I'm cleaning the relay pins right now as I type they weren't corroded but they were really discolored, is that corrosion for them? which one is the fuel relay? Also where is the crank sensor so I can tap on it.

There are loose wires in some places, but I had the engine idle and messed with all them and nothing happened. All the grounds look okay, but i'll recheck.

and wooo go Texas!!!!

(My favorite state)

79Mercy · #4 11-10-2009, 05:33 PM

Im wondering if the fuel pump is about to die. When you turn the key does it make wierd noises?

WOW, 50,000 RPM thats pretty fast, LOL, JK.

JordaanDMC-12 · #5 11-10-2009, 05:44 PM

Quote:

Originally Posted by 79Mercy

Im wondering if the fuel pump is about to die. When you turn the key does it make wierd noises?

WOW, 50,000 RPM thats pretty fast, LOL, JK.

It doesn't make any weird noises but I'm questioning it as well... LOL that's the speed I roll at

79Mercy · #6 11-10-2009, 05:53 PM

When it will not start do you smell gas when trying to start the engine?

Have you checked the crankshaft position sensor?

JordaanDMC-12 · #7 11-10-2009, 11:10 PM

Quote:

Originally Posted by 79Mercy

When it will not start do you smell gas when trying to start the engine?

Have you checked the crankshaft position sensor?

No, I don't smell gas, I did when we first got it but I put a new gas cap on it and fixed the rubber seal that connects to the filler tube and it fixed that problem.

Where is that sensor located?

79Mercy · #8 11-10-2009, 11:12 PM

the sensor is mounted on the block and it senses when the motor has made a full revolution, there is a stud or something on the vibration dampner that the sensors senses each time it goes around.

long-gone · #9 11-11-2009, 12:04 AM

On a 91 300E the sensor is mounted on a small bracket that is suspended just above the harmonic balance on the driver's side. A small tang on the left side of the bracket acts as the timing mark indicator. There should be a wire that travels from one of the harness clusters on the drivers side fender well - under the front of the intake - up over the water pump - and then down to the balance past the belt tensioner shock. The exact path may differ but that should be close. It's somewhat buried down there, but you can see it with the right angle and a flashlight.

Be REAL careful trying tap it or jiggle the wires as you'd be dangerously close to a lot of moving parts while the engine is running.

It's held on with one small nut (8mm?) on a slightly long threaded stud. It's bit of a pricey part (maybe $50-75 ??, I haven't looked in a while). If I strongly suspected it, I'd probably see if I could get one from a junk yard ($5-10) and swap it out.

Some other things you might also want to check are the OVP relay, the air flap in the throttle body (they get gummed up and stick) which should move nearly effortlessly, the idle-air solenoid, the fuel pressure regulator and maybe the ignition coil (in about that order). It doesn't sound like a vacuum issue, which aren't generally intermittent like that.

Good luck, if you find the cause, do follow up and let us know.

dhjenkins · #10 11-11-2009, 09:01 AM

When you tried to rev it and it wouldn't get past 2,000 - 3,000 rpm, were you just stomping on the pedal repeatedly? When you did so, did it stumble, misfire or shake at all?

How much gas is in your tank and do you get quality gas?

JordaanDMC-12 · #11 11-11-2009, 01:12 PM

I picked my dad up from dropping a car off from detail half an hour ago and he bumped into an old friend with a Kia that had the EXACT same issue as the 300E.

He said the reason was because the fuel pump in the gas tank had a filter with little pellets to cleanse the fuel, but that filter broke and the pellets got sucked into the fuel pump and would clog it up. When he let the car sit it would start right back up because the pellets had backed off. What makes this even more plausible despite the fact he had 100% the exact same symptoms as I is that the gas tank in the 300E had been messed with by the PO and we had to realign it and move it around. I don't know if Mercedes used this "pellet" set up (probably not considering it was Kia lol) but it seems like that is it!

Where is the fuel pump located on the 300E? The fuel tank?

JordaanDMC-12 · #12 11-11-2009, 01:14 PM

Quote:

Originally Posted by dhjenkins

When you tried to rev it and it wouldn't get past 2,000 - 3,000 rpm, were you just stomping on the pedal repeatedly? When you did so, did it stumble, misfire or shake at all?

How much gas is in your tank and do you get quality gas?

Yes, I was flooring it and basically try to get some response from the engine. When I did, the engine would sputter and sound like it was about to backfire. Like it wasn't getting fuel...

We've had about half a tank of Chevron premium and lucas fuel system cleaner.

79Mercy · #13 11-11-2009, 01:16 PM

Fuel pump is located rehind the right rear wheel.

Thats pobably not the problem, the pellets would have been caught in the filter. Replace the filter theres a good chance its clogged.

JordaanDMC-12 · #14 11-11-2009, 01:33 PM

Quote:

Originally Posted by 79Mercy

Fuel pump is located rehind the right rear wheel.

Thats pobably not the problem, the pellets would have been caught in the filter. Replace the filter theres a good chance its clogged.

Awesome, will do!

dhjenkins · #15 11-11-2009, 02:23 PM

A clogged filter isn't usually an intermittant problem...